I just want to say how strong the characters will be
God Serena, Spriggan 12, Dragon king(Grandeeney) are stronger than the admirals. Two admirals will be needed to stop them and three to defeat them.
Mystogan, Jellal have the strength equilavent to the admirals.
Zeref at 100% is equivalent to IMU/Joyboy
At fairy heart form he is stronger than both combined